Active pressure control and fault monitoring method

Abstract

A medical system for monitoring pressure can include a medical device having an inflatable element, at least one pressure sensor in communication with the inflatable element, and a control unit. The control unit can include a fluid source in fluid communication with the inflatable element, and circulation of the fluid within the inflatable element can cause the inflatable element to inflate. Processing circuitry can be configured to monitor pressure within the inflatable element based on signals received from the at least one pressure sensor over a first time period and circulation of the fluid within the inflatable element over a second time period.

Description

[0001] Cross-reference to related applications

[0002] not applicable. Technical Field

[0003] This technology generally relates to cryoablation devices with expandable therapeutic elements, as well as active pressure control, leak monitoring, and detection methods and systems for expandable therapeutic elements. Background Technology

[0004] Cardiac arrhythmias and other heart conditions are widely treated using catheters with expandable therapeutic elements. Because this type of medical device is not particularly widespread in terms of use and can target local tissues, these catheter-based devices are suitable for a wide variety of medical and surgical applications and environments. Catheters with expandable therapeutic elements can be inserted into the body and navigated through blood vessels to the target site with minimal trauma to the body.

[0005] Inflating and deflating expandable therapeutic elements can be necessary for placing catheters within the body and delivering localized treatment to hard-to-reach areas. For example, ablation and cryoablation treatments can be delivered to certain tissues using expandable therapeutic catheters. These expandable therapeutic elements are filled and pressurized with gas or fluid and can be moved to different parts of the body via blood vessels. Effective contact with tissue may require moving, positioning, anchoring, retaining, and altering the shape of the expandable therapeutic element to suit specific areas of the tissue being treated. Even minute changes in the orientation and pressure of the expandable therapeutic element can significantly affect the extent of treatment delivered to a particular tissue area. The effectiveness and efficiency of ablation and / or cryoablation procedures can depend on the pressure maintained within the expandable therapeutic element during the procedure and on the manner and location of its placement within the body.

[0006] Additionally, the operation of catheters with expandable therapeutic elements may require that fluids or gases injected into the expandable therapeutic element remain contained within the catheter at all times. Leaks in any part of the expandable therapeutic element and / or catheter can cause significant harm to the patient receiving treatment. For example, if a one-piece expandable therapeutic element develops a crack, leak, rupture, or other breach in structural integrity, fluids or gases may leak out of the catheter and into the body. Summary of the Invention

[0007] The technology disclosed herein generally relates to cryoablation of tissue using a cryoablation device with an expandable therapeutic element, and to active pressure control, leak monitoring, and detection systems and methods for the expandable therapeutic element. In one embodiment, a medical system for monitoring pressure includes: a medical device comprising: an expandable element; at least one pressure sensor in communication with said expandable element; a control unit including: a fluid source in fluid communication with said expandable element, wherein fluid circulation within said expandable element causes said expandable element to expand; and processing circuitry configured to monitor the pressure within said expandable element for a first time period based on signals received from at least one of said pressure sensors and to circulate said fluid within said expandable element for a second time period.

[0008] In one aspect of the implementation, the processing circuit alternates between two phases: monitoring the pressure within the expandable element during a first time period; and maintaining fluid circulation within the expandable element for a predetermined time period during a second time period.

[0009] In one aspect of the implementation, the predetermined time period is the duration of the medical procedure.

[0010] In one aspect of the implementation, the first time period and the second time period are the same time period.

[0011] In one aspect of the implementation, the first time period is longer than the second time period.

[0012] In one aspect of the implementation, the first time period is shorter than the second time period.

[0013] In one aspect of the implementation, when the processing circuit monitors the pressure within the expandable element based on a signal received from at least one of the pressure sensors, fluid circulation within the expandable element stops.

[0014] In one aspect of the implementation, as the fluid circulates within the expandable element, the expandable element is inflated to a preset pressure, and then the processing circuit stops the fluid circulation within the expandable element during a third time period.

[0015] In one aspect of the implementation, the processing circuit is configured to accept a predetermined pressure threshold, and when the pressure in the expandable element exceeds the predetermined pressure threshold, the processing circuit indicates a fault condition.

[0016] In one aspect of the implementation, the processing circuit indicates a fault condition when the pressure in the expandable element drops below the predetermined pressure threshold.

[0017] In one aspect of the implementation, the fault condition terminates fluid circulation in the expandable element.

[0018] In one embodiment, a medical system for monitoring pressure includes: a medical device comprising: an expandable element; a control unit comprising: a fluid source in fluid communication with the expandable element, wherein circulation of fluid within the expandable element causes the expandable element to expand to a preset pressure range, and wherein once the pressure of the expandable element is within the preset pressure range, the fluid source provides preset periodic expansion pulses to the expandable element; and a processing circuit configured to monitor at least one of the duration and frequency of the preset periodic expansion pulses to determine any change in at least one of the frequency and duration of the preset periodic expansion pulses.

[0019] In one aspect of the implementation, the inflatable element is a balloon.

[0020] In one aspect of the implementation, the preset pressure range is adjustable.

[0021] In one aspect of the implementation, the frequency and duration of the periodic expansion pulses are adjustable.

[0022] In one aspect of the implementation, a change in at least one of the frequency and duration of the preset periodic expansion pulse indicates a fault condition.

[0023] In one aspect of the implementation, the fault condition provides at least one of notification and activation of a system response.

[0024] In one aspect of the implementation, the system response is to discharge fluid from the medical device.

[0025] In one aspect of the implementation, the fluid source is a cryogenic fluid.

[0026] In one embodiment, a medical system for monitoring pressure includes: a medical device comprising: an expandable element; at least one pressure sensor in communication with the expandable element; and a control unit configured to operate in a first mode and a second mode: in the first mode, during a first time period, fluid circulation within the expandable element causes the expandable element to expand, and during a second time period, a program monitors the pressure within the expandable element based on signals received from at least one of the pressure sensors; in the second mode, fluid circulates within the expandable element and expands the expandable element to a preset pressure range, and then a fluid source provides a preset periodic expansion pulse to the expandable element, wherein a processing circuit is configured to monitor the preset periodic expansion pulse provided to the expandable element and determine any change in at least one of the frequency and duration of the preset periodic expansion pulse.

[0027] Details of one or more aspects of the invention are set forth in the following drawings and description. Other features, objects, and advantages of the technology described in this disclosure will become apparent from the specification, drawings, and claims. Attached Figure Description

[0028] A more complete understanding of the invention and its accompanying advantages and features will be more readily obtained by referring to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 An exemplary medical system of the present disclosure is shown, which includes a cryoablation device having an expandable element;

[0030] Figure 2 A graph of exemplary data is shown, illustrating the pressure of the expandable element and processing circuitry alternating between active pressure control and leak detection monitoring phases, where the pressure is maintained within a predetermined threshold.

[0031] Figure 3 A graph showing exemplary data illustrates the pressure of the expandable element and processing circuitry alternating between active pressure control and leak detection monitoring phases, where the pressure drops below a predetermined threshold and triggers a fault condition.

[0032] Figure 4 A graph illustrating exemplary data is provided, demonstrating the pressure of the expandable element and the processing circuitry that provides sustaining pulses at predetermined times, wherein the pressure is maintained within a predetermined threshold by periodic sustaining pulses; and

[0033] Figure 5 A graph of exemplary data is shown, illustrating the pressure of the expandable element and the processing circuitry that provides sustaining pulses at an increased frequency. Detailed Implementation

[0034] The apparatus, system, and method disclosed herein are used to assess pressure in an expandable element and monitor for any fluid and / or gas leakage from the expandable element. In one embodiment, a medical system for assessing pressure in an expandable element and monitoring leakage includes an elongated body and an expandable element, the elongated body including a distal portion and a proximal portion, and the expandable element being coupled to the distal portion of the elongated body. The expandable element may have a first expandable element and a second expandable element, with the first expandable element contained within the second expandable element. The expandable element may have more than two expandable elements or may be a single expandable element.

[0035] Before describing the exemplary embodiments of this disclosure in detail, it should be noted that components are indicated by conventional symbols in appropriate places in the drawings, which only show some specific details relevant to the understanding of the embodiments of this disclosure, so as to avoid obscuring this disclosure by details that would be obvious to those skilled in the art who would benefit from the description herein.

[0036] As used herein, relational terms such as “first,” “second,” “top,” and “bottom” may be used solely to distinguish one entity or element from another without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the concepts described herein. As used herein, the singular forms “a,” “an,” and “described” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that, when used herein, the terms “comprising,” “including,” “including,” and / or “containing” specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0037] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that, unless expressly defined herein, terms used herein shall be interpreted as having the same meaning as they have in the context of this specification and related art, and shall not be interpreted in an idealized or overly formal sense.

[0038] In the embodiments described herein, the conjunction "communicating with" and the like can be used to indicate electrical or data communication, which may be achieved through physical contact, induction, electromagnetic radiation, radio signals, infrared signals, or optical signals. Those skilled in the art will understand that multiple components can interoperate and be modified and altered to achieve electrical and data communication.

[0039] It should be understood that the various aspects disclosed herein can be combined with combinations different from those specifically presented in the specification and drawings. It should also be understood that, based on examples, certain actions or events of any of the processes or methods described herein may be performed in a different order, added, combined, or omitted entirely (e.g., all described actions or events may not be necessary for performing the technique). Furthermore, although certain aspects of the invention are described for clarity as being performed by a single module or unit, it should be understood that the technology of the invention can be performed by combinations of units or modules associated with, for example, a medical device.

[0040] In one or more examples, the described techniques can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality can be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media can include non-transitory computer-readable media, which correspond to tangible media such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store the required program code in the form of instructions or data structures and is accessible by a computer).

[0041] Instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, the term "processor" as used herein can refer to any of the foregoing structures or any other physical structure suitable for implementing the technology. Furthermore, the technology can be entirely implemented in one or more circuit or logic elements.

[0042] Referring now to the accompanying drawings, in which similar reference numerals denote similar elements, and embodiments of the medical system are described in... Figure 1 As shown, it is generally designated as "10". Components of the apparatus are indicated by conventional symbols in appropriate places in the drawings, which only show some specific details relevant to the understanding of embodiments of this disclosure, so as to avoid obscuring this disclosure by details that would be obvious to those of ordinary skill in the art who benefit from the description herein. Furthermore, while the specific embodiments or drawings described herein may illustrate features not explicitly pointed out in other drawings or embodiments, it should be understood that the features and components of the systems and apparatuses disclosed herein are not necessarily mutually exclusive and can be implemented in various different combinations or configurations without departing from the scope and spirit of the invention.

[0043] Continue to refer to Figure 1 An exemplary medical system 10 for cryoablation is illustrated. One embodiment of the medical system 10 typically includes a treatment device such as a cryoablation treatment device 12 and a control unit 14 communicating with the cryoablation treatment device 12. The cryoablation treatment device 12 may include one or more diagnostic or therapeutic elements 16 for interacting energy or other therapeutic effects between the cryoablation treatment device 12 and the treatment site. The therapeutic elements 16, for example, are capable of delivering cryotherapy and may also be configured to deliver radiofrequency ablation or otherwise transfer energy to tissue regions near the treatment area, including cardiac tissue. In particular, one or more therapeutic elements 16 may be configured to lower the temperature of adjacent tissue to perform cryotreatment and / or cryoablation. Furthermore, the cryoablation treatment device 12 can be used for treatment, denervation, or neuromodulation.

[0044] Continue to refer to Figure 1 The treatment element 16 may include one or more balloons (such as...) Figure 1 The balloon(s) shown are expandable and / or inflatable elements, and coolant circulates within the balloon(s) to lower the temperature of the balloon(s)18, thereby lowering the temperature of the tissue in contact with and / or adjacent to the balloon(s)18. In the context of this application relating to balloon(s)18 and / or (multiple) balloons, it should be understood that this may also refer to (multiple) expandable and / or (multiple) inflatable elements, and balloon(s)18 are merely exemplary embodiments. Additionally, in some embodiments, balloon(s)18 include other thermally and / or electrically conductive elements such as one or more electrodes (not shown) communicating with the control unit 14. Furthermore, although one balloon(s)18 is shown in the figures, it should be understood that the cryoablation treatment device 12 may include more than one balloon(s)18 arranged adjacent to and / or stacked on top of each other. For example, treatment element 16 may include a first balloon located within a second balloon(s) (not shown).

[0045] Continue to refer to Figure 1 In one embodiment, in addition to the treatment elements(s) 16, the cryoablation treatment device 12 also includes a longitudinal axis 20 and typically includes a handle 22 and an elongated body 24 connected to the handle 22. The elongated body 24, such as a catheter, sheath, or intravascular guide, can be sized and configured to pass through a patient's blood vessels and / or be positioned close to the tissue area to be diagnosed or treated. The elongated body 24 may have a proximal portion 26 coupled to the handle 22 and a distal portion 28 opposite to the proximal portion 26, and may also include one or more lumens disposed within the elongated body 24 providing mechanical, electrical, and / or fluid communication between the proximal portion 26 and the distal portion 28 of the elongated body 24.

[0046] In one embodiment, at least a portion of the treatment elements 16 is coupled to the distal portion 28 of the elongated body 24. In one embodiment, the cooling ablation treatment device 12 further includes a shaft member 30 movable along the length of the elongated body 24 (e.g., the central cavity of the elongated body 24), such that the shaft can advance and retract within the elongated body 24. In one embodiment, at least one treatment element 16 includes a balloon 18 having a distal neck 32 and a proximal neck 34, with the distal neck 32 coupled to the distal tip 36 of the shaft member 30 and the proximal neck 34 coupled to the distal portion 28 of the elongated body 24. In this configuration, movement of the shaft member 30 within the elongated body 24 affects the shape and / or structure of the balloon 18. For example, when the balloon 18 is fully deflated and in the delivery (or first) configuration, the shaft member 30 can be fully extended, wherein the balloon 18 has, for example, a minimum diameter suitable for retracting the cooling ablation treatment device 12 within a sheath for delivery and / or retraction from the target treatment site. Conversely, when balloon 18 is inflated or inflated and in the therapeutic (or second) structure, shaft member 30 can influence the inflation or inflation of balloon 18 (e.g., as...). Figure 1 (As indicated by the double arrows in the diagram) The distance of the dimension and / or structure advances or retracts. Additionally, shaft member 30 may include a conduit lumen allowing sensors, transducers, wires, or other system components to pass through.

[0047] Continue to refer to Figure 1 In one embodiment, the balloon 18 has an internal chamber 38, and the cooling ablation treatment device 12 further includes one or more nozzles, orifices, or other fluid delivery elements 40 for delivering fluids such as coolant to the internal chamber 38 of the balloon 18. During operation, according to one embodiment, coolant flows from a coolant supply reservoir 42 through a fluid flow path located in at least a portion of the elongated body 24 of the cooling ablation treatment device 12 to the balloon 18. The coolant then expands to cool the balloon 18 and enters the internal chamber 38 of the balloon 18, for example, through the fluid delivery elements 40(s). The expanded coolant then flows from the internal chamber 38 of the balloon 18 to a coolant recovery container 44 and / or a degassing / venting system (not shown).

[0048] Continue to refer to Figure 1One embodiment of the medical system 10 further includes a pressure sensing system 46 comprising a pressure sensor 48 (e.g., a pressure sensor) located within a handle and / or control unit 14 and / or a pitot tube 50 in fluid communication with the pressure sensor 48. In one embodiment, the pressure sensor 48 is located within a handle 22, and the pitot tube 50 extends from the pressure sensor 48 into an internal chamber 38 within the balloon 18. The pitot tube 50 includes one or more orifices (not shown) configured to be exposed to fluid and / or gas circulating within the internal chamber 38 when the cryoablation treatment device 12 is in use. According to known principles, the pitot tube 50 and the pressure sensor 48 measure dynamic pressure based on the difference between stagnant pressure and static pressure. Therefore, in one embodiment, the sensing system 46 is configured to measure pressure within the internal chamber 38 in relation to the pressure of the balloon 18. In some embodiments, the cryoablation treatment device 12 and / or control unit 14 include one or more additional sensors, such as temperature sensors, flow rate sensors, pressure sensors, impedance sensors, etc.

[0049] Continue to refer to Figure 1 In one embodiment, the control unit 14 typically includes one or more containers comprising a coolant supply reservoir 42, a coolant recovery container 44, and other components of the fluid flow path, such as a vacuum pump 52 for creating a low-pressure environment within one or more channels of the fluid flow path, such that expanding coolant is discharged from the internal chamber 38 of the balloon 18 to the proximal portion 26 of the elongated body 24 and into the coolant recovery container 44. In some embodiments, the control unit 14 also includes an energy generator (not shown). As used herein, the term “control unit” refers to any component of the medical system 10 other than components of the cryoablation treatment device 12 itself, whether such components are physically located inside or outside the control unit 14.

[0050] Continue to refer to Figure 1In one embodiment, the control unit 14 further includes one or more controllers, processors, and / or software modules containing instructions or algorithms to provide automated or semi-automated operation and execute the features, sequences, or programs described herein. In one embodiment, the control unit 14 includes a computer 54 having a display 56 and processing circuitry 58 programmed or programmable to perform automated or semi-automated operation and the features, sequences, calculations, and / or programs described herein. In one embodiment, the processing circuitry 58 includes a memory and a processor, the memory including instructions that, when executed by the processor, configure the processor to receive, process, or otherwise use signals from the cryoablation treatment device 12 and / or other system components. Additionally, in some embodiments, the control unit 14 further includes one or more user input devices 60 (e.g., keyboard, touchscreen, keypad, buttons, knobs, etc.), controllers, speakers, and / or displays that communicate with the processing circuitry 58 and are used to collect information from and transmit information to the user.

[0051] Continue to refer to Figure 1 The processing circuitry 58 can communicate with the sensing system 46 and can be configured to monitor the pressure within the balloon 18 in real time based on signals received from the pressure sensor 48 and the pitot tube 50. Alternatively, the sensing system 46 may include a pressure monitoring circuit that includes the pressure sensor 48, which may be located within the control unit 14. The pressure within the balloon 18 can be measured by the pressure sensor 48 in the control unit 14. For example, the internal chamber 38 of the balloon 18 can communicate with the pressure monitoring circuitry of the control unit 14 via, for example, an injection tube or vacuum passage between the balloon 18 and the control unit 14, thereby enabling the measurement of the pressure within the balloon 18. Generally, it is necessary to control the pressure within the balloon 18 so that the balloon 18 can be inflated or deflated within different pressure ranges that may be required to achieve certain clinical goals. When real-time pressure control is required in a particular medical procedure, the sensing system 46 may not detect leaks in the balloon 18 because the cryoablation device 12 may be able to compensate for some leaks by, for example, increasing fluid circulation within the balloon 18. However, in some medical procedures, even a small loss of pressure can affect the stiffness and rigidity of the balloon 18, making it difficult for it to exert its occlusive effect under certain pressures.

[0052] Now refer to Figure 2In one embodiment, the control unit 14 may be configured to alternate between active pressure control 64 and a leak detection and monitoring phase 66. In active pressure control 64, the balloon 18 may inflate to a specific preset pressure target 62, wherein a coolant supply reservoir 42 is in fluid communication with the balloon 18, and coolant may flow from the coolant supply reservoir 42 through its inner cavity to the balloon 18 and inflate the balloon 18 to the preset pressure target 62. Processing circuitry 58 may be configured to detect whether the balloon 18 has inflated to the preset pressure target 62. It should be understood that although coolant is generally referred to, any fluid or gas that inflates the balloon 18 may be used. The pressure target 62 may be a specific pressure or may include a range of pressures throughout the medical procedure. In one embodiment, active pressure control 64 may occur when the control unit 14 inflates the balloon 18 to the pressure target 62. For example, the pressure target 62 may be set within different pressure ranges, allowing the balloon 18 to inflate and / or deflate to various different pressures. For example, balloon 18 can inflate to a positive pressure relative to atmospheric pressure, and as a non-limiting example, balloon 18 can inflate to a pressure between 20 psi and 120 psi. The pressure in balloon 18 can be set to vary depending on the type of balloon 18 used, the procedure being performed, and the patient's anatomy. Active pressure control 64 is capable of maintaining balloon 18 at a preset pressure for a period of time during which coolant continuously flows into balloon 18 from coolant supply reservoir 42. Alternatively, active pressure control 64 can maintain balloon 18 at a preset pressure for a period of time by periodically injecting coolant from coolant supply reservoir 42 into balloon 18. Once balloon 18 inflates to the preset pressure target 62, control unit 14 is capable of stopping fluid circulation within balloon 18 for a period of time. In medical system 10, the pressure in balloon 18 can be temporarily increased based on the initial cooling effect of the fluid and / or gas whenever fluid and / or gas are initially injected into balloon 18. However, the pressure within balloon 18 may decrease once the fluid and / or gas within balloon 18 is heated by the body, including any tissue and / or blood near balloon 18. Control unit 14 can be configured to recognize the following temporary pressure changes: the initial injection of fluid and / or gas into balloon 18 causes a temporary increase in pressure within balloon 18, which may then decrease when the gas / fluid is heated by the body. When control unit 14 recognizes this pressure change, it can be identified as a normal pressure fluctuation that does not trigger any alarms, system responses, and / or notifications. The amount of coolant or other gas or fluid flowing into balloon 18 from coolant supply reservoir 42 can be adjusted based on the cooling dose required to maintain pressure target 62 within balloon 18. This can be customized for the specific medical procedure being performed and the needs and requirements of the patient undergoing the procedure.The pressure target 62 can be maintained at the same pressure throughout the medical procedure, or the control unit 14 can be configured to adjust the pressure target 62 at specific preset time intervals throughout the medical procedure or to adjust the pressure target 62 according to the body structure targeted by the medical device 10. Alternatively, the user can manually input the pressure target 62 into the control unit 14, for example, by using the input device 60. Adjustment can be made by manually inputting the pressure target 62 if an unexpected situation arises during the medical procedure that requires a change in the pressure target 62 within the balloon 18.

[0053] Continue to refer to Figure 2The control unit 14 can also be configured to prevent the continuous inflow of coolant from the coolant supply reservoir 42 into the balloon 18 via active pressure control 64. When active pressure control 64 is disabled, the control unit 14 can enter a leak detection monitoring phase 66. In the leak detection monitoring phase 66, the control unit 14 can use the pressure sensor 48 and the pitot tube 50 in the sensing system 46 to actively monitor the pressure of the balloon 18 when coolant is not flowing into the balloon 18 from the coolant supply reservoir 42 to determine any pressure changes within the balloon 18, or to monitor the pressure anywhere in the cryoablation device 12. The control unit 14 may have specific preset parameters for the pressure target 62 to indicate whether any pressure loss in the balloon 18 or anywhere else in the cryoablation device 12 is within a preset pressure range. The medical system 10 including the cryoablation device 12 may also include a safety pressure monitoring system to detect unwanted pressure build-up outside the internal chamber 38 of the balloon 18 and inside the cryoablation device 12. The preset parameters for pressure target 62 may include pressure changes measured from an initial pressure level, such as -0.5 psi measured from the initial pressure level, or may be based on the measured rate of pressure change over time, such as a pressure change of less than 1 psi / min over a time range of (t) seconds. Pressure change levels may also be configured to respond to different time ranges, such as less than 1 psi / min over 10 seconds, less than 2 psi / min over 2 seconds, or less than 5 psi / min over 0.2 seconds. Including pressure level changes configured to respond to different time ranges allows for a faster response to larger pressure changes and provides the medical system 10 with more time to assess smaller pressure changes, reducing the risk of reporting leaks in the absence of leaks. Furthermore, some changes in pressure in balloon 18 during leak detection monitoring phase 66 may be normal and expected, although other pressure changes in balloon 18 may indicate a leak in balloon 18 or elsewhere in the medical system 10. Pressure leaks unrelated to the structural integrity of balloon 18 may exist within the medical system 10. For example, a pressure leak of less than approximately 0.1 psi / min can be normal and is expected within medical system 10. The range of pressure losses considered normal and expected within any particular medical system 10 can be set based on the parameters of that particular system and can vary based on the requirements of medical system 10 and the procedures being performed. If the pressure of balloon 18 remains within pressure target 62 during leak detection monitoring phase 66, control unit 14 can return to active pressure control 64.Alternatively, if the pressure of balloon 18 drops before the pressure target 62 changes, control unit 14 can keep cryoablation device 12 in leak detection monitoring phase 66, thereby not supplying fluid and / or gas to balloon, and / or can stop operation of cryoablation device 12 so that any fluid and / or gas that may leak from balloon 18 will not be released into the patient's body.

[0054] exist Figure 2 In one embodiment shown, the control unit 14 can be configured to alternate between active pressure control 64 and leak detection and monitoring phase 66. Figure 2 In this process, the duration of active pressure control 64 can be set to be the same as the duration of leak detection and monitoring phase 66. For example, during a medical procedure, control unit 14 can be configured to be in active pressure control 64 for one (1) minute in a first time period A, then alternate to leak detection and monitoring phase 66 and maintain it for one (1) minute in a second time period B, such that the alternation between the first time period A and the second time period B occurs during the medical procedure. Alternatively, the alternation time between the first time period A and the second time period B can be less than the duration of the medical procedure, a preset time period, or manual control. The duration of active pressure control 64 can also be set differently from leak detection and monitoring phase 66. For example, control unit 14 can be configured to be in active pressure control 64 for 1 to 2 seconds in the first time period A, then alternate to leak detection and monitoring phase 66 and maintain it for 10 seconds in the second time period B. The durations of active pressure control 64 and leak detection and monitoring phase 66 can also not be fixed and / or can change over time. In another embodiment, during the medical procedure, control unit 14 may be configured to be in active pressure control 64 for one (1) minute in a first time period A, and then alternate to leak detection monitoring phase 66 for thirty (30) seconds in a second time period B; or control unit 14 may be configured to be in active pressure control 64 for thirty (30) seconds in the first time period A, and control unit 14 may be configured to be in active pressure control 64 for one (1) minute in the second time period B. Control unit 14 may also be configured to remain in active pressure control 64, or optionally remain in leak detection monitoring phase 66 without alternation. For example, if a potential leak is detected in balloon 18 or anywhere else in cryoablation treatment device 12 during leak detection monitoring phase 66, control unit 14 may be configured to remain in leak detection monitoring phase 66 to prevent additional gas and / or fluid from being diverted into balloon 18 in the presence of a leak.

[0055] Now refer to Figure 3In the initial phase, active pressure control 64 can be used to inflate balloon 18 to the pressure target 62 by circulating fluid and / or gas into balloon 18. Once balloon 18 has inflated to the pressure target 62, active pressure control 64 can maintain the pressure of balloon 18 within the pressure target 62. After active pressure control 64 inflates balloon 18 to the pressure target 62, control unit 14 can terminate active pressure control 64 for a period of time and activate leak detection monitoring phase 66, in which the pressure of balloon 18 and / or any pressure within cryoablation treatment device 12 is actively monitored for a period of time. During leak detection monitoring phase 66, if control unit 14 determines that any pressure change anywhere within balloon 18 and / or cryoablation treatment device 12 exceeds a predetermined threshold 68, control unit 14 can indicate a fault condition 70. The predetermined threshold 68 can be based on pressure changes relative to the current pressure and / or value or pressure changes over time. The value set as the predetermined threshold 68 can depend on the procedure being executed, the balloon 18 being used, and the design of control unit 14. Fault condition 70 may be a notification such as an audible alarm on computer 54, a visual alarm on display 56, and / or a tactile alarm. The alarm can provide information including pressure information of balloon 18, pressure information anywhere within cryoablation device 12, and information related to any suspected leaks in balloon 18 or any other part of cryoablation device 12. Additionally and / or alternatively, fault condition 70 can activate a system response, for example, shutting down cryoablation device 12 and / or any part thereof, to, for example, prevent fluids and / or gases from entering the patient's body from medical system 10. If fault condition 70 activates the system response, the system response can remove refrigerant from balloon 18, and this process can be achieved by applying a vacuum to remove refrigerant from balloon 18 to prevent refrigerant leakage into the patient's bloodstream. The system response may also involve collecting information to determine the location and / or cause of a leak, which can then be provided by the user of medical system 10 to aid in diagnosing the problem. This information collection can occur during and / or after the removal of any refrigerant from medical system 10. In one implementation, such as Figure 3 As shown, a fault condition 70 is triggered once the pressure anywhere within the balloon 18 and / or the cryoablation treatment device 12 drops below a predetermined threshold 68. If fault condition 70 is triggered, the control unit 14 may not return to active pressure control 64, but notifications and alarms may appear on the medical system 10, and a system response may occur to prevent fluids and / or gases from escaping from the medical system 10 and entering the body.

[0056] Now refer to Figure 4In another embodiment, control unit 14 may be configured to initially trigger active pressure control 64 to inflate balloon 18 to a preset pressure within pressure target 62. Active pressure control 64 may be set to inflate balloon 18 to the preset pressure within a specified time period. If balloon 18 fails to inflate to the preset pressure within the specified time period, fault condition 70 may be triggered, and a notification and / or alarm may be issued and / or a system response may be triggered. Failure of balloon 18 to inflate to the preset pressure within the specified time period may indicate a leak in balloon 18 or elsewhere in the medical system 10. During active pressure control 64, sensing system 46 is capable of continuously monitoring the pressure within balloon 18 or other locations within the medical system 10.

[0057] Continue to refer to Figure 4If balloon 18 inflates to a preset pressure within pressure target 62 within a specified time period, the control unit can trigger at least one sustaining pulse 72 to maintain the inflation pressure of balloon 18. During the time period of sustaining pulse 72 triggered by control unit 14, sensing system 46 can continue to monitor the pressure within balloon 18 and / or other locations in medical system 10. Control unit 14 can be configured to continuously monitor the pressure within balloon 18 and other locations in medical system 10, including during inflation and deflation of balloon 18. Sustaining pulse 72 may be a predetermined amount of fluid from coolant supply reservoir 42, which is delivered through the lumen to balloon 18 for a preset time period and continues for a preset duration to maintain the inflation pressure in balloon 18. Various parameters can be set based on, for example, the volume of balloon 18 and cryoablation treatment device 12, for the predetermined amount of fluid delivered through the lumen to balloon 18 within the preset time period from coolant supply reservoir 42. For example, a sustaining pulse 72 may include a pulse with sufficient fluid and / or gas to increase the pressure in balloon 18 by approximately 0.01 psi per pulse. However, the amount of fluid and / or gas in each sustaining pulse 72 may vary depending on the size of balloon 18, the design of control unit 14, the length of the catheter, and other variables. This may be pre-programmed into medical system 10 or configured based on the medical system 10 in use. At least one sustaining pulse 72 may be preset in control unit 14 for a preset time period, or a manually determined time period, based on the balloon 18 pressure during the ongoing procedure and medical procedure. Thus, once balloon 18 is inflated to the desired pressure, medical system 10 will only need to use sustaining pulses 72 for periodic re-inflation to maintain the desired pressure within balloon 18. Although medical system 10 may experience some anticipated pressure loss within balloon 18, anticipated pressure loss over a specific time period can be programmed into control unit 14 so that sustaining pulses 72 can be used at preset times to maintain the pressure within balloon 18 for a preset period. Based on the expected pressure loss over a specific time period equal to the pressure of a specific balloon 18, the control unit 14 can be configured to initiate a sustaining pulse 72 using a predetermined amount of fluid during a preset time interval. If there is no leakage in the balloon 18, the sustaining pulse 72 is expected to occur at preset time intervals using a predetermined amount of fluid, while continuing to maintain the pressure of the balloon 18 within the pressure target 62.

[0058] Now refer to Figure 5If the frequency and / or duration of the maintenance pulse 72 changes from a preset time interval using a predetermined amount of fluid, the control unit 14 may indicate a fault condition 70 to trigger a notification, alarm, and / or system response. In one embodiment, the maintenance pulse 72 may be preset to produce a specific amount of fluid and / or gas every (1) minute, said fluid and / or gas being released into the balloon 18 during each maintenance pulse 72. The sensing system 46 may be configured to monitor the pressure of the balloon 18 and / or another part of the medical system 10 before, during, and after the maintenance pulse 72. If the pressure of the balloon 18 and / or the other part of the medical system 10 drops below a predetermined pressure threshold between any maintenance pulses 72, the control unit 14 may activate the maintenance pulse 72 at different frequencies and / or for different amounts of fluid released into the balloon 18 during each maintenance pulse 72. In one example, if the maintenance pulse 72 begins to occur at a frequency greater than once every (1) minute, and / or more than a specific amount of fluid is released into the balloon 18 during the maintenance pulse 72 to maintain the pressure of the balloon 18, the fault condition 70 may be triggered. Variations in the amount, duration, and / or frequency of the maintenance pulse 72 can indicate a leak in balloon 18, and a fault condition can trigger notifications, alarms, and / or system responses to prevent further leakage of any fluid and / or gas from medical system 10 into the patient. Any preset time period can be set to trigger each individual maintenance pulse 72, and any amount of fluid and / or gas can be set to be released from coolant supply reservoir 42 into balloon 18 during each maintenance pulse 72. Control unit 14 is capable of detecting any changes in the frequency of maintenance pulse 72 occurrence and / or the amount of fluid and / or gas released into balloon 18 during each maintenance pulse 72. Any changes detected by control unit 14 may trigger fault condition 70.

[0059] Those skilled in the art will understand that the present invention is not limited to what has been specifically shown and described above. Furthermore, unless otherwise stated above, it should be noted that all drawings are not to scale. Based on the above teachings, various modifications and variations can be made without departing from the scope and spirit of the invention, which is limited only by the appended claims.

Claims

1. A medical system for monitoring pressure, wherein, include: Medical devices, including: Expandable elements; At least one pressure sensor communicating with the expandable element; and Control unit, including: A fluid source in fluid communication with the expandable element, the circulation of fluid within the expandable element causing the expandable element to expand; and The processing circuitry is configured to alternate between an active pressure control phase and a leak monitoring and detection phase. The active pressure control phase includes, during a first time period, circulating the fluid within the expandable element according to a predetermined target pressure. The leak monitoring and detection phase includes monitoring the pressure within the expandable element based on signals received from at least one of the pressure sensors during a second time period, wherein When the pressure change in the expandable element does not exceed a predetermined threshold during the leak monitoring and detection phase, the processing circuit repeats the active pressure control phase. When the pressure change in the expandable element exceeds the predetermined threshold during the leak monitoring and detection phase, the processing circuit indicates a fault condition and stops the active pressure control phase.

2. The medical system according to claim 1, wherein, The processing circuit alternates between the active pressure control phase and the leak monitoring and detection phase within a predetermined time period.

3. The medical system according to claim 2, wherein, The predetermined time period is the duration of the medical procedure.

4. The medical system according to claim 1, wherein, The first time period and the second time period are the same time period.

5. The medical system according to claim 1, wherein, The first time period is longer than the second time period.

6. The medical system according to claim 1, wherein, The first time period is shorter than the second time period.

7. The medical system according to claim 1, wherein, When the processing circuit monitors the pressure within the expandable element based on signals received from at least one of the pressure sensors, fluid circulation within the expandable element stops.

8. The medical system according to claim 1, wherein, As fluid circulates within the expandable element, the expandable element is inflated to a preset pressure, and then the processing circuit stops the fluid circulation within the expandable element during a third time period.

9. The medical system according to claim 1, wherein, The processing circuit is configured to a predetermined pressure threshold, and when the pressure in the expandable element exceeds the predetermined pressure threshold, the processing circuit indicates a fault condition.

10. The medical system according to claim 9, wherein, When the pressure in the expandable element drops below the predetermined pressure threshold, the processing circuit indicates a fault condition.

11. The medical system according to claim 10, wherein, The fault condition terminates the fluid circulation in the expandable element.

12. A medical system for monitoring pressure, wherein, include: Medical devices, including: Expandable elements; and Control unit, including: A fluid source in fluid communication with the expandable element circulates fluid within the expandable element to expand it to a preset pressure range. Once the pressure of the expandable element is within the preset pressure range, the fluid source provides preset periodic expansion pulses to the expandable element to maintain the preset pressure range. The processing circuit is configured as follows: The duration and frequency of the preset periodic expansion pulse are monitored periodically to determine whether at least one of the frequency and duration of the preset periodic expansion pulse changes. When the pressure in the expandable element falls below the threshold pressure, the preset periodic expansion pulses are stopped being supplied to the expandable element, indicating a fault condition.

13. The medical system according to claim 12, wherein, The expandable element is a balloon.

14. The medical system according to claim 12, wherein, The preset pressure range is adjustable.

15. The medical system according to claim 12, wherein, The frequency and duration of the preset periodic expansion pulse are adjustable.

16. The medical system according to claim 12, wherein, A change in at least one of the frequency and duration of the preset periodic expansion pulse indicates a fault condition.

17. The medical system according to claim 16, wherein, The fault condition provides at least one of notification and activation of the system response.

18. The medical system according to claim 17, wherein, The system response is to discharge fluid from the medical device.

19. The medical system according to claim 12, wherein, The fluid source is a cryogenic fluid.

20. A medical system for monitoring pressure, wherein, include: Medical devices, including: Expandable elements; At least one pressure sensor communicating with the expandable element; and The control unit is configured to operate in a first mode and a second mode: The first mode includes, during a first time period, circulating fluid through the expandable element, causing the expandable element to expand, and during a second time period, using processing circuitry to monitor the pressure within the expandable element based on signals received from at least one of the pressure sensors; and The second mode includes circulating fluid within the expandable element to expand the expandable element to a preset pressure range. A preset periodic expansion pulse is provided to the expandable element using a fluid source. The preset periodic expansion pulses supplied to the expandable element are periodically monitored. Determine any variation in at least one of the frequency and duration of the preset periodic expansion pulse, and When the pressure in the expandable element exceeds or falls below the preset pressure range, a fault condition is indicated and the supply of the preset periodic expansion pulse to the expandable element is stopped.

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